InP/InGaAs buried-structure avalanche photodiodes

Planar InP/InGaAs avalanche photodiodes with a new guardring structure have been designed and fabricated. The diodes had a buried n-InP layer and an n−-InP multiplication region under p-n junctions. A successful guardring effect was obtained. The diode exhibited a uniform multiplication over the active region, a maximum multiplication factor of 30, low dark currents of around 20 nA at 90% of breakdown voltage and a flat frequency response up to 1 GHz. Multiplication noise was measured up to a multiplication factor of 17.